Field of the Invention
The present invention relates to an injector controlling method using an opening duration, and more particularly, to a method for controlling an actuation signal of an injector using an opening duration by converting a target fuel quantity of the injector into the opening duration.
Background Art
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A fuel injection type of a vehicle engine is generally divided into a port injection type and a direct injection type. Here, the port injection type is mainly used in a gasoline engine and adopts the way to supply fuel-air mixture to the inside of a cylinder by injecting fuel to an intake port.
The direction injection type is mainly used in a diesel engine and adopts the way to directly inject fuel to the inside of the cylinder.
However, recently, technology to adopt the direct injection type to the gasoline engine with the purposes of improvement of fuel efficiency and output and prevention of environmental pollution is in the spotlight. Such an engine is called a GDI (Gasoline Direct Injection) engine, and is the way that air is inhaled to a combustion chamber from an intake port and is compressed by a piston and fuel is directly injected relative to air of high pressure introduced into the combustion chamber when an intake valve is opened.
The GDI engine has injectors respectively mounted on cylinders to inject fuel at high pressure. A solenoid of each injector injects fuel into the combustion chamber by opening an injection outlet when receiving an actuation signal from a controller, and then, closes the injection outlet when injection is finished.
However, even though the injection outlets of the injectors are opened at the same time, the injectors are different from one another in the time that the injection outlets are closed due to differences in abrasion and deterioration of the injectors, internal friction of needles or internal friction of an amateur and a difference in elastic modulus of a return spring, and hence, the fuel quantity injected by the injector is varied.
The conventional technologies have adopt the method of controlling the injector by converting the target fuel quantity into an actuation signal through a map in which relationship between the target fuel quantity and the actuation signal for actuating the injector is set.
However, as described above, the conventional method has several disadvantages in that the injectors are different in the degree of opening from one another even though the same actuation signal is applied to the injectors, in that it is difficult to accurately control the fuel quantity even though various calibrated maps because the injector actuation time and the degree of opening of the injectors are not simply proportional to each other, and in that problems, such as combustion instability and excessive discharge of particulate matters if the quantity of fuel injected is small.